ATTannenbaum

It’s that special time of year again where the smell of baking cookies fill the house and shopping mall parking lots are filled with idiots and very angry people. [Kevin] thought it would be a good idea to build an LED Christmas tree and ended up building a great looking tree that’s also very simple.

In the video, the imgur album, and the github, [Kevin] shows us the simplest way to make a color-changing LED Christmas tree. The circuit uses LEDs to drop the voltage and to provide a nice glow around the base of the tree. After that, it’s just an ATtiny13 and some LEDs in a very nice freeform circuit.

Of course, if LED Christmas trees aren’t your thing, [hb94] over on reddit created an LED menorah. Pretty nifty he used an 8-position DIP switch for the circuit. Let’s just hope someone gave him a soldering iron for the last night of Hanukkah.

Clever! I particularly like the RGB LEDs. But I have to wonder why it needs a microcomputer?

Way back in 1986, I was broke and needed something for Christmas presents. I came up with a Christmas tree that used a CD4093, wired as 4 RC oscillators. Each output drove two LEDs, one high and one low. A capacitor in series instead of the usual resistor eliminated the power lost in a resistor. A ninth LED was in series with the battery, to provide a flickering “start” on top (and reversed battery protection).

I’ve made hundreds of them since! You can see it at http://www.sunrise-ev.com or get one assembled on eBay item# 271124335043.

To build an RGB tree, how about using a 74HC132 (hex schmitt trigger) for six oscillators? Use half common-anode and half common-cathode RGB LEDs, wired to the 6 oscillators in a matrix.